Androgen induced growth factor (AIGF) is a factor isolated in 1992 from a culture supernatant of a mouse mammary tumor cell line SC-3 (Shionogi Carcinoma-3: J. Steroid Biochem., 27, 459 (1987)! which shows sex hormone-dependent growth. AIGF is a growth factor which is induced and produced by androgen stimulation and activates growth of SC-3 cells in an autocrine manner Proc. Natl. Acad. Sci., 89, 8928-8932, (1992)!. The results of gene cloning efforts revealed that it has a homology of 30 to 40% with the FGF family at the amino acid level, and it was named fibroblast growth factor-8 (hereinafter referred to as "FGF-8"). Thereafter, human FGF-8 was cloned from a human placenta genomic library using mouse FGF-8 as a probe, which coincided with the mouse FGF-8 by a factor of 85% at the nucleotide level and 100% at the amino acid level FEBS Letters, 363, 226 (1995)!. It has been assumed that sex hormone induced growth factors would exhibit an autocrine role in tumors such as prostatic cancer, and breast cancer which show sex hormone-dependent growth, and the isolation and cloning of FGF-8, though in a mouse system, was the first evidence of such a mechanism. It is probable that FGF-8 also plays a role in carcinogenesis and tumor growth in humans by a similar mechanism, but clear evidence has not yet been obtained. However, since expression of FGF-8 m-RNA can be found in several human tumor cell lines of prostatic cancer and breast cancer and enhancement of cell growth can be observed when FGF-8 expressed in CHO cells is added to the culture system of these cell lines or a cell line of fibroblasts FEBS Letters, 363, 226 (1995)!, it is highly possible that FGF-8 is one of the growth factors which act on sex hormone-dependent tumors in an autocrine or paracrine manner.
In consequence, an antibody specific for FGF-8 is useful for the analysis of the role and biological function of FGF-8 in the above-mentioned tumor cells, and also for the diagnosis of prostatic cancer, breast cancer and the like by immunological detection. Also, it appears that the antibody having a neutralization activity would be useful in studying biological activities of FGF-8 and effective in treating the cancers.
To date the isolation of a monoclonal antibody specific for FGF-8 has not been reported.